def encode_int24(self, value):
if value < 0 or value > 16777215:
raise ValueError('value out of range')
raw = [value & 63, value >> 6 & 63, value >> 12 & 63, value >> 18 & 63]
if self.big:
raw = reversed(raw)
return join_byte_elems(imap(self._encode64, raw))
def _encode_int(self, value, bits):
pad = -bits % 6
bits += pad
if self.big:
itr = irange(bits - 6, -6, -6)
value <<= pad
else:
itr = irange(0, bits, 6)
return join_byte_elems(
imap(self._encode64, (value >> off & 63 for off in itr)))
def encode_bytes(self, source):
if not isinstance(source, bytes):
raise TypeError('source must be bytes, not %s' % (type(source), ))
chunks, tail = divmod(len(source), 3)
if PY3:
next_value = nextgetter(iter(source))
else:
next_value = nextgetter(ord(elem) for elem in source)
gen = self._encode_bytes(next_value, chunks, tail)
out = join_byte_elems(imap(self._encode64, gen))
return out
def decode_bytes(self, source):
if not isinstance(source, bytes):
raise TypeError('source must be bytes, not %s' % (type(source), ))
chunks, tail = divmod(len(source), 4)
if tail == 1:
raise ValueError('input string length cannot be == 1 mod 4')
next_value = nextgetter(imap(self._decode64, source))
try:
return join_byte_values(
self._decode_bytes(next_value, chunks, tail))
except KeyError as err:
raise ValueError('invalid character: %r' % (err.args[0], ))